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JEE CHEMISTRY MCQ: P-BLOCK ELEMENTS

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Assertion (A) Elementary phosphorus exists in three principal allotropic forms, i.e. white (or yellow), red (or violet) and black.

Reason (R) Of the three forms, white phosphorus is the most important and most reactive.

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Correct option: A

If both Assertion and Reason are true and Reason is correct explanation of Assertion.

Option A (If both Assertion and Reason are true and Reason is correct explanation of Assertion) is correct because white phosphorus is indeed the most reactive allotrope due to its unstable tetrahedral structure.

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The gas used for inflating the tyres of aeroplanes is: Which of the following is correct stability order of oxides of

17^{\text {th }}

group elements is: Assertion: Ozone is a powerful oxidising agent in comparison to

{O}_2

.

Reason: Ozone is diamagnetic but

{O}_2

is paramagnetic. Which of the following is kept in water?

\mathrm{C}{\mathrm{N}^ - }

{\mathrm{N}_2}

are isoelectronic but in contrast to

\mathrm{C}{\mathrm{N}^ - },\mathrm{\;}{\mathrm{N}_2}

is chemically inert because of: Consider the following statements

(i) Reaction

2 {Fe}^{3+}+{SO}_2+2 {H}_2 {O} \rightarrow 2 {Fe}^{2+}+{SO}_4^{2-}+4 {H}^{+}

shows reducing character of sulphur dioxide

(ii)

{H}_2 {~S}_2 {O}_8

{S}={O}

{S}-{OH}

{O}-

{O}

{NH}_3

gas can be dried effectively by using conc.

{H}_2 {SO}_4

.

(iv) One of the major use of

{H}_2 {SO}_4

is in the manufacture of fertilizers.

Which of the following is the correct code for the statements above?